Breath coordinated inhaler

ABSTRACT

An improved breath coordinated inhaler is provided for administering medication to a patient in aerosol form for respiratory inhalation therapy. The improved inhaler comprises a compact housing adapted to receive and support a medication cannister including a valve assembly actuatable to deliver a dosage of the medication in aerosol form. The housing includes a plunger mounted at a first end thereof for displacing the cannister against a spray nozzle located at a second end of the housing to actuate the valve assembly and deliver the medication through a mouthpiece to the patient. The plunger is associated with a seal arrangement for venting the housing when the plunger is depressed to allow the patient to draw in air in timed relation to the medication delivery, and to substantially re-seal the housing against ingress of contaminants when the plunger is released.

This is a continuation of application Ser. No. 08/829,466, filed on Mar.28, 1997, now U.S. Pat. No. 5,904,139.

BACKGROUND OF THE INVENTION

This invention relates generally to respiratory inhalers of the typeused to deliver a selected medication in aerosol form to a patient,wherein the medication is drawn by inhalation directly into the lungs ofthe patient. More specifically, this invention relates to an improvedinhaler of relatively compact and simplified construction, wherein theinhaler is vented for breath coordinated inhalation of air andmedication in a regulated timed manner, but further wherein entry ofcontaminants into the inhaler between uses is substantially prevented.

Respiratory inhaler devices are generally known in the art foradministering a selected medication typically in aerosol form directlyinto the lungs of a patient to treat a wide variety of medicalconditions, such as asthma, bronchitis, and the like, and also fortreating other nonrespiratory conditions wherein the lungs represent thesite-of-delivery for a selected medication. In one common form, theinhaler comprises a compact hand-held housing for receiving andsupporting a cannister containing the selected medication in liquid formunder pressure. The cannister is equipped with a reciprocal valveassembly adapted for depression to deliver a single metered dose of themedication through a spray nozzle which propels the medication inaerosol form through a mouthpiece for direct inhalation by the patient.In use, the patient places the mouthpiece in his or her mouth andattempts to inhale in timed relation to manipulation of the cannisterand housing to depress the valve assembly, in an effort to draw asubstantial portion of the medication deeply into the lungs.

To enhance the delivery of the medication to the patient's lungs, breathcoordinated inhalers have been developed wherein air is drawn by thepatient through the inhaler housing in synchronized relation to thedelivery of the medication. That is, by allowing air to flow through thehousing and to be inhaled as the medication is sprayed, the medicationcan be entrained within a substantial volume of air for better ingestioninto the lungs and resultant better administration of the medication.However, the provision of an air pathway through the inhaler housingalso provides an open housing construction that is highly susceptible toentry of dirt and other contaminants between uses to administer themedication. In this regard, between uses, the inhaler is often carriedabout by the patient in a pocket or purse whereat undesired entry ofcontaminants into the inhaler housing is likely to occur.

Attempts to reconfigure the inhaler housing to accommodate breathcoordinated inhalation yet reduce or eliminate undesired entry ofcontaminants between uses has met with limited success. Vented inhalerhousings designed to restrict ingress of contaminants between uses havebeen relatively complex and thus relatively costly in construction, andfurther have typically resulted in a substantial increase in the overallsize and shape of the inhaler housing. Moreover, absent a substantialincrease in the size and shape of the inhaler housing, such ventedhousings have not provided a simple and reliable way to provide auniform stroke length for the cannister valve assembly tocorrespondingly provide uniform doses of the medication, notwithstandingcannister dimension and tolerance variations which occur during normalmanufacture.

There exists, therefore, a continuing need for further improvements inbreath coordinated inhalers, particularly with respect to providing arelatively simple and compact and cost effective inhaler housingconstruction that is substantially closed to entry of contaminantsbetween uses, and further wherein the compact inhaler housing isdesigned to accommodate dimensional variations in themedication-containing cannister. The present invention fulfills theseneeds and provides further related advantages.

SUMMARY OF THE INVENTION

In accordance with the invention, an improved breath coordinated inhaleris provided for administering medication in aerosol form to a patient.The inhaler comprises a compact housing for receiving and supporting amedication containing cannister or cartridge of a type having aspring-loaded valve assembly actuated by depression to deliver a metereddose of a selected liquid medication contained under pressure within thecannister. The inhaler housing includes a plunger at one end thereof fordepression to engage the cartridge in a manner depressing the valveassembly against a spray nozzle to release the medication dose through amouthpiece at an opposite end of the housing. The plunger is associatedwith a seal arrangement which opens to provide an air pathway throughthe housing for breath coordinated inhalation when the plunger isdepressed, and which closes upon release of the plunger to substantiallyprevent entry of dirt and other contaminants into the inhaler housingbetween uses. With this construction, the air pathway is closed when theplunger is not depressed, such that the patient can inhale theair-entrained medication only when the plunger is depressed to open theair pathway.

In the preferred form of the invention, the inhaler housing has a hollowinterior adapted to receive the medication cannister in an invertedorientation with a tubular stem of the valve assembly engaging the spraynozzle formed within the housing at a lower end thereof generallyadjacent to the mouthpiece. The upper end of the inverted cannisterengages a seal disk mounted within the housing for movement between anopen position permitting air flow through one or more vents disposed inthe upper end of the housing, and a closed position substantiallypreventing air flow through said vent. The seal disk is displaced bydepression of the plunger for movement from the closed position to theopen position, and to displace the cannister relative to the spraynozzle to depress the cannister valve assembly. Accordingly, plungerdepression opens the housing vent and operates the cannister valveassembly in synchronized relation to permit the patient to inhale viathe mouthpiece a substantial air volume with the medication entrainedtherein. When the plunger is released, a spring may be provided forreturn of the seal disk to its original position closing the vent.Alternately, the spring-loaded valve assembly of the cannister may beused for urging the cannister against the seal disk for return to thenormal position closing the vent.

The inhaler housing is formed from a pair of slidably intermittinghousing members assembled together with the medication cannistertherein. These housing members may be slidably press-fitted oralternately adhesively connected. In either case, the interfittinghousing members accommodate dimensional tolerance variations in themedication cannister, thereby insuring plunger depression sufficient todisplace the cannister valve assembly through a full stroke each timemedication is delivered to the patient.

Other features and advantages of the invention will become more apparentfrom the following detailed description, taken in conjunction with theaccompanying drawings which illustrate, by way of example, theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate the invention. In such drawings:

FIG. 1 is a perspective view of a breath coordinated inhaler embodyingthe novel features of the invention;

FIG. 2 is a vertical sectional view taken generally on the line 2--2 ofFIG. 1;

FIG. 3 is a vertical sectional view similar to FIG. 2, and illustratingdepression of a plunger to deliver a dosage of medication to a patient;

FIG. 4 is an exploded vertical sectional view showing assembly of theinhaler components;

FIG. 5 is an enlarged top plan view of a housing for the inhaler, takengenerally on the line 5--5 of FIG. 4;

FIG. 6 is a perspective view showing one alternative preferred form ofthe invention;

FIG. 7 is a vertical sectional view of the embodiment of FIG. 6; and

FIG. 8 is an exploded perspective view depicting assembly of thecomponents of the embodiment of FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in the exemplary drawings, an improved inhaler referred togenerally by the reference numeral 10 in FIG. 1 is provided for breathcoordinated inhalation of a selected medication used for respiratorytherapy. The improved inhaler 10 is adapted to receive and support acompact cannister or cartridge 12 (FIGS. 2-4) containing the selectedmedication in liquid form under pressure and including a spring-loadedvalve assembly 14 for delivering the medication in metered doses. Theinhaler 10 includes one or more vents 16 located in the end of aninhaler housing 18, wherein these vents 16 are normally closed toprevent undesired entry of dirt and other contaminants into the interiorof the inhaler housing. However, when the inhaler is operated as will bedescribed to deliver a dose of the medication, the vents are opened insynchronized relation to operation of the cannister valve assembly 14,to permit a patient to inhale a significant volume of air with themedication dose entrained therein.

The medication cannister 12 comprises a conventional and widely usedproduct in the form of a small and typically metal cannister containingthe selected medication in liquid form under pressure, for delivery ofthe medication to the patient in the form of an aerosol spray. Thecannister 12 normally includes the valve assembly 14 mounted directlyinto an open end of the cannister, as by roll forming the cannister tocapture and retain the valve assembly components. As depicted in FIGS.2-4, the valve assembly includes a reciprocal tubular stem 20 associatedwith internally mounted valve elements (not shown) including a spring 22for spray delivery of a metered dose of the medication each time thestem is depressed. This medication cannister construction and operationis well known in the art, and thus is not further shown or describedherein.

In general terms, the inhaler housing 18 is sized and shaped forreceiving and supporting the medication cartridge 12 in an invertedorientation, with the tubular stem 20 of the valve assembly 14 seatedwithin a sump forming a spray nozzle 24 located within the housing 18 ata lower end thereof and in a position adjacent to an open mouthpiece 26.More particularly, the inhaler housing 18 is constructed with arelatively compact size and shape, and is conveniently formed from amolded plastic or the like. The housing 18 defines a hollow interior 28for receiving the cannister 12, with the spray nozzle 24 formedintegrally with a lower housing wall. The spray nozzle 24 defines anupwardly open port 30 sized for slide-fit reception of the end of thecannister stem 20 in a position seated upon a small shoulder. The openport 30 is disposed in flow communication with a nozzle orifice 32 andassociated expansion spray segment 34 for directing the aerosol dosageof the medication outwardly to a patient through the open mouthpiece 26,as viewed in FIG. 3. The housing is sized to permit air flowtherethrough, from the vent 16 to the mouthpiece 26, when the vents 16are opened as will be described.

The inhaler housing 18 carries a plunger 36 mounted at an upper endthereof in an exposed position outside the housing. The plunger 36 isprovided for displacing the medication cannister 12 in a downwarddirection within the housing, resulting in depression of the tubularstem 20 of the valve assembly 14. The plunger 36 is thus manipulated tooperate the valve assembly 14 to deliver a dose of the medicationthrough the mouthpiece. In use, the patient places the mouthpiece 26into his or her mouth (not shown), and then depresses the plunger 36 todeliver the dose of the medication through the mouthpiece. Substantiallyat the time of medication delivery, the patient attempts to inhale forthe purpose of drawing a substantial portion of the sprayed medicationdeeply into the lungs.

The plunger 36 is associated with a seal arrangement designed tonormally close the inhaler housing 18 against entry of dirt and othercontaminants. However, the seal arrangement is operated by the plunger36 to open the vents 16 when the plunger is depressed to permit air flowinto the top of the housing when medication is delivered to the patient.Accordingly, when the plunger is depressed, the upper end of the housing18 is opened to air flow so that the patient can inhale a substantialvolume of air in coordinated or synchronized relation to the medication.The coordinated inhalation of air and medication entrains the medicationin the air volume and thus enhances delivery of the medication to deepor lower lung zones.

As shown best in FIGS. 2-5, the seal arrangement comprises a seal disk38 mounted within the inhaler housing 18 at the inboard side of thehousing upper end. The seal disk, which may be formed from or otherwiselined with a resilient seal material, has a size and shape to overliethe vents 16 in order to close and seal the vents when the seal disk 38engages the housing upper end. A central stem 40 protrudes upwardly fromthe seal disk 38 for passage through a central port 42 formed in anupper end wall 44 of the housing 18, and subsequent connection as bypress-fit or adhesive attachment within an aperture 46 formed in thedisk-shaped plunger 36. As shown, the upper end wall 44 of the housingincludes a plurality of upwardly arched leaf-type springs 48 which areconveniently formed integrally with the end wall 44, and which bias theplunger 36 upwardly to a normal position carrying the seal disk 38 intosealed engagement with the inboard side of the end wall 44 to close thevents 16. Alternately, it will be recognized that the spring 22 of thecannister valve assembly 14 provides a similar biasing force urging thecannister upwardly to carry the seal disk 38 toward the normal positionclosing the vents 16, whereby the leaf springs 48 or other springdevices at the top of the housing 18 can be omitted.

In operation, the seal disk 38 is normally retained by the spring forcein the closed position sealed against the inboard side of the upper endwall 44 of the inhaler housing 18. In addition, a closure cap (notshown) is also normally provided for closing the mouthpiece 26 at thelower end of the housing 18. Accordingly, the interior 28 of the inhalerhousing 18 is normally closed against entry of dirt and the like whichcan otherwise enter and contaminate the inhaler as the device is carriedabout by the patient in a pocket or purse. However, when a dose of themedication is desired, removal of the referenced closure cap and meredepression of the plunger 36 opens the vents 16 to allow a substantialvolume of air to be drawn into and through the housing interior 28 andfurther through the mouthpiece 26, in synchronized or timed relation tothe plunger-caused displacement of the cannister to deliver the dose ofthe medication. In this regard, the open area defined by the vents 16can be closely selected and designed to regulate the air volume drawnthrough the housing for medication entrainment. Similarly, the geometryof the plunger 36 and the seal disk 38 can be tailored to regulate thetiming between the opening of the vents 16 and the actual delivery ofthe medication dose for substantially optimum entrainment of themedication and administration to deep lung zones. When the plunger 36 isreleased, the spring force automatically returns the seal disk 38 to theclosed position sealing the vents 16.

In accordance with a further aspect of the invention, the inhalerhousing 18 can be designed to accommodate variations in the specificheight dimension of the medication cannister 12, thereby to accommodatemanufacturing tolerance variations which could otherwise affect thedisplacement stroke length of the cannister when the plunger 36 isdepressed. More particularly, as shown in FIGS. 1-3, the preferredhousing construction comprises a slidably interfitting generallycup-shaped pair of upper and lower housing members 50 and 52, withmatingly overlapping segments referenced by arrow 53, wherein theseoverlapping segments 53 can be press-fitted together or adhesivelyinterconnected. The overlapping segments 53 are sized to provide alongitudinal tolerance sufficient to accommodate normal heightvariations in the medication cannister 12, so that the cannister isfirmly seated at both the opposite ends thereof with the tubular stem 20seated within the spray nozzle 24 and an upper end engaging the sealdisk 38. In this way, the seal disk 38 is securely retained in sealedrelation with the housing end wall 44 in the normal closed position. Inaddition, a full stroke length of the cannister 12 and the associatedstem 20 is assured each time the plunger 36 is depressed, for deliveryof the full metered dose of the medication to the patient. In thisarrangement, by positioning the plunger 36 at the upper end of thehousing 18, a full stroke length is provided without requiring anysignificant increase to the overall size, shape or profile of theinhaler device.

An alternative preferred form of the invention is shown in FIGS. 6-8,wherein modified components corresponding in structure and function tothose shown and described in FIGS. 1-5 are identified by commonreference numerals increased by 100. As shown, a modified breathcoordinated inhaler 110 is provided with a plunger 136 adapted toinclude a counter 54 to track the number of medication doses deliveredfrom the device. The inhaler 110 also includes a modified mouthpiece 126including an elongated inhaler tube 56 mounted onto the inhaler housing118 by a pivot pin 57 for pivoting movement between a stored position(FIG. 7) and an outwardly projecting active position for use (FIGS. 6and 8).

The modified inhaler 110 includes the hollow inhaler housing 118 with aspray nozzle 124 formed therein at a lower end thereof adjacent to theopen mouthpiece 126. The spray nozzle 124 is adapted to receive thetubular stem 20 of an inverted medication cannister 12 in the samemanner as previously shown and described. The inhaler 118 is sized andshaped for close-fit reception of the cannister 12 and includes theplunger 136 and vented seal arrangement at the housing upper end.

More particularly, as shown best in FIGS. 7 and 8, a modified seal disk138 is mounted within the inhaler housing and comprises a generallycup-shaped element inverted to fit over the upper end of the invertedmedication cartridge 12. The seal disk 138 defines an outer rim toinclude a plurality of short spacer tabs 58 for providing an air pathwaybetween the outer periphery of the seal disk 138 and the inner surfaceof an upper housing member 150. An upwardly projecting stem 140 isformed on the seal disk 138 and extends through an open port 142 in theupper housing member 150 for press-fit or snap-fit or adhesiveattachment to a boss 60 on the plunger 136. A lower portion of this stem140 is defined by a larger diameter seal ring segment 61 having a sizeand shape to sealingly close the housing port 142 when the seal disk 138is positioned substantially in engagement with the inboard side of theupper end wall 144 of the upper housing member 150.

When the plunger 136 is depressed, the seal disk 138 and the medicationcannister 12 are displaced through a downward stroke in the same manneras previously described with respect to FIGS. 1-5. In particular, thedownward movement of the seal disk 138 moves the seal ring segment 61out of the housing port 142 to permit air flow into and through theinhaler housing 118. The corresponding downward movement of thecannister 12 results in discharge of a metered dose of the medication tothe mouthpiece. The medication is thus entrained within the air flow forinhalation by the patient into the patient's lungs. Importantly, thegeometry of the seal ring segment 61 and the related housing port 142can be closely controlled to regulate the air volume drawn through thedevice and further to control the timing of medication dischargerelative to venting of the housing via the port 142.

The plunger 136 conveniently includes the counter 54 adapted fordetecting each downward stroke of the plunger to deliver a medicationdose. An electronic display is provided on a side of the plunger toindicate the number of doses which have been delivered, or the number ofdoses remaining in the cannister. The particular mechanism used in thecounter to detect downward plunger strokes may vary and will beunderstood by persons skilled in the art. Moreover, it will berecognized that the counter device is optional and may be omitted.

The inhaler housing 118 comprises the slidably interfitting upper andlower housing members 150 and 152 for accommodating dimensionalvariations in the specific medication cannister 12, as previouslydescribed. In the embodiment of FIGS. 6-8, the upper housing member 150is shown for sliding fit into a matingly shaped lower housing member152. A stop ring 64 is provided within the lower housing member 152 toprovide a mechanical stop preventing overinsertion of the upper housingmember 150 with the plunger 136 mounted thereon.

More particularly, in the embodiment of FIGS. 6-8, initial assembly ofthe upper housing members 150 is performed with the plunger 136 and therelated seal disk 138. This subassembly is then adapted for installationas a unit with the lower housing member 152. In this regard, in anassembly line production environment, a specific medication cannister 12can be associated with a lower housing member 152, and the stop ring 64is inserted into the lower housing member 152 at a specific depthcorresponding to the height dimension of the matched cannister 12. Thestop ring 64 can be installed as a simple press-fit, or desirablyattached by adhesive bonding or sonic welding or the like. Thereafter,the lower housing member 152 and its associated medication cannister 12can be assembled with an upper housing member subassembly as describedabove for packaging and shipment. The stop ring 64 provides a fixedmechanical stop for correct sliding fit of the upper and lower housingmembers 150, 152 according to the actual height dimension of thecannister 12. The housing members can be periodically disassembled forcleaning, if desired, and subsequently re-assembled in the correctslide-fit relation.

The improved breath coordinated inhaler of the present invention thusprovides a relatively simple construction for permitting patientinhalation of air with an entrained dose of the selected medication,resulting in a highly efficacious administration of the medication.However, the invention further provides an effective seal arrangementfor substantially closing the interior of the inhaler housing betweenuses, to substantially prevent ingress of dirt and other contaminants.The vent and seal arrangement is provided at the upper end of theinhaler housing to result in a highly compact inhaler construction whichis relatively cost efficient to produce and assemble in productionquantities, and which further is adapted to accommodate tolerancevariations in standard medication cannisters.

A variety of further modifications and improvements in and to the breathcoordinated inhaler of the present invention will be apparent to thosepersons skilled in the art. Accordingly, no limitation on the inventionis intended by way of the foregoing description and accompanyingdrawings, except as set forth in the appended claims.

What is claimed is:
 1. A breath coordinated inhaler for use with amedication cannister containing a selected medication under pressure andhaving a spring-loaded valve assembly for delivering a metered dose ofthe medication in aerosol form, said inhaler comprising:a housing havinga hollow interior for receiving and supporting the medication cannisterin an inverted orientation, said housing defining an upper end with atleast one vent formed therein and a lower end, said housing furtherdefining an open mouthpiece generally at said lower end; spray nozzlemeans within said housing generally at said lower end for engaging thecannister valve assembly; a non unitary seal means disposed within saidhousing generally at said upper end for normally overlaying and closingsaid vent; spring means associated with said seal means for normallyretaining said seal means in a closed position overlying and closingsaid vent; and plunger means mounted at said housing upper end andcoupled to said seal means, said plunger means being depressable to movesaid seal means to an open position spaced from said vent and further tomove the medication cannister within said housing whereby the cannistervalve assembly is operated by said spray nozzle means to deliver a doseof the medication through said mouthpiece.
 2. The breath coordinatedinhaler of claim 1 wherein said spring means reacts between said housingand said plunger means.
 3. The breath coordinated inhaler of claim 2wherein said spring means is formed integrally with said housing.
 4. Thebreath coordinated inhaler of claim 1 wherein said seal means comprisesa seal disk mounted within said housing at an inboard side of saidhousing upper end.
 5. The breath coordinated inhaler of claim 4 whereinsaid seal disk is connected to said plunger means by a stem extendingthrough an open port formed in said housing upper end.
 6. The breathcoordinated inhaler of claim 1 wherein said housing is formed by a pairof slidably interfitting, generally cup-shaped housing members.
 7. Thebreath coordinated inhaler of claim 6 further including stop means forlimiting sliding interfit of said housing members.
 8. The breathcoordinated inhaler of claim 7 wherein said stop means comprises a stopring mounted within one of said housing members.
 9. The breathcoordinated inhaler of claim 1 wherein said seal means comprises a sealdisk mounted within said housing at an inboard side of said upper end,and a connector stem extending through an open port formed in saidhousing upper end to interconnect said seal disk and said plunger means,said connector stem having a cross sectional size whereby said open portforms said vent when said seal disk is displaced by said plunger meansto said open position.
 10. The breath coordinated inhaler of claim 9wherein said seal disk cooperates with said housing to define an airpathway between said vent and said mouthpiece.
 11. The breathcoordinated inhaler of claim 1 wherein said plunger means is depressableto move said seal means against the medication cannister to displace thecannister within said housing.
 12. A breath coordinated inhaler,comprising;a medication cannister containing a selected medication underpressure and including a spring-loaded valve assembly at one end thereoffor depression to deliver a metered dose of the medication; an inhalerhousing having a hollow interior for receiving and supporting saidcannister, said housing defining an upper end with at least one ventformed therein and a lower end, said housing further defining an openmouthpiece generally at said lower end; a spray nozzle mounted withinsaid housing generally at said lower end for engaging said cannistervalve assembly; a non unitary seal member disposed within said housinggenerally at said upper end and movable between a closed positionoverlying and closing said vent and an open position spaced from saidvent to permit air flow through said vent and further through saidhousing to said mouthpiece; a spring means on said housing associatedwith said seal member for urging said seal member normally to saidclosed position; and a plunger connected to said seal member anddisposed outside said housing at said upper end thereof, said plungermeans being depressable to move said seal member from said closedposition to an open position and further to move said seal memberagainst said cannister whereby said cannister valve assembly is actuatedby said spray nozzle to deliver a metered dose of the medication throughsaid mouthpiece, said valve assembly providing a spring force urgingsaid seal member to return to said closed position upon release of saidplunger.
 13. The breath coordinated inhaler of claim 12 wherein saidseal member is connected to said plunger by a stem extending through anopen port formed in said housing upper end.
 14. The breath coordinatedinhaler of claim 13 wherein said stem has a cross sectional size wherebysaid open port forms said vent when said seal member is in said openposition.
 15. The breath coordinated inhaler of claim 12 wherein saidhousing is formed by a pair of slidably interfitting, generallycup-shaped housing members.
 16. The breath coordinated inhaler of claim15 further including stop means for limiting sliding interfit betweensaid housing members.
 17. The breath coordinated inhaler of claim 16wherein said stop means comprises a stop ring mounted within one of saidhousing members.